JP2002314797A - Image file containing image processing control data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that ensures output of an image subjected to image processing, which reflects the color reproduction characteristics of a shooting device and the intention of a photographer in shooting. SOLUTION: The process generates an image file that includes picture data generated by a digital still camera, as well as control data and output specification information attached thereto. The control data controls the details of image processing according to the color reproduction characteristics of the camera and the intention of the photographer in shooting. The image processing information is embedded to the image data by electronic watermark technology. A printer extracts the image picture information subjected to electronic watermark embedding from the image data and applies image processing based thereon, and after that executes printing. Thus, the printing reflecting the intention of the photographer in shooting or the like can be realized and tampering or the like of the image processing information can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for outputting an image using an image file containing image data and image processing information of the image data.

[0002]

2. Description of the Related Art In recent years, digital still cameras (DS)
C), image data is generated by an imaging device such as a digital video camera (DVC), a scanner, etc.
2. Description of the Related Art A method of outputting an image using an output device such as a T, an LCD, a printer, a projector, and a television receiver is becoming widespread. In such image output, the brightness and color of the subject may not be able to be faithfully reproduced due to a difference in color reproduction characteristics between the imaging device and the output device. Conventionally, such differences in color reproduction have been corrected by retouching image data.

[0003]

However, since such retouching requires a very advanced technique, the adjustment is difficult and complicated. Although application software that automatically corrects the color tone and sharpness by analyzing image data has been proposed, the correction is not sufficient because the characteristics of the imaging device are not reflected. In addition, there are cases where the intention of the photographer is rather spoiled due to unnecessary correction or the like.

As a method of avoiding such a problem, a method of transferring information such as the characteristics of the imaging device and the intention of the photographer to the output device together with the image data, performing correction based on the information, and outputting the corrected data is conceivable. However, if the information passed along with the image data can be easily falsified, the intention of the photographer may be eventually lost. In addition, information such as the characteristics of the imaging apparatus and the intention of the photographer is a kind of know-how, and therefore needs to be kept secret from a third party.

[0005] The present invention has been made in view of these problems, and it is possible to avoid the possibility of leakage to a third party, falsification, and the like, and to produce an output reflecting the characteristics and intention at the time of creating image data. The aim is to provide enabling technologies.

[0006]

In order to solve at least a part of the above-mentioned problems, the present invention provides a method of creating image data in image data by using a so-called digital watermarking technique. And the information necessary to communicate the intentions shall be embedded. The necessary information can be, for example, image processing control data for specifying image processing to be performed on the image data.

[0007] An image data generating apparatus for realizing such embedding includes, for example, original image data input means, image processing control data setting means, and image data generating means. The original image data input means inputs original image data to be subjected to image processing. The input of the original image data includes, for example, modes such as shooting by an imaging device, generation by computer graphics, and input of already generated image data. The image processing control data setting means sets image processing control data for specifying the content of image processing to be performed on the original image data. The image processing control data may be stored in the image data generating device in advance, or may be input from outside.

The image data generating means generates image data in which image processing control data is digitally watermarked and embedded in original image data. Digital watermarking refers to a technique for embedding specific data in original image data in a state in which it is invisible. In the present invention, any digital watermarking technology may be applied.

The image data according to the present invention includes image processing control data. The image processing apparatus can specify the image processing to be performed on the image data based on the image processing control data, and can perform the image processing without impairing the characteristics and intention at the time of generating the image data. Further, in the present invention, since the image processing control data is embedded in the form of a digital watermark, the contents can be concealed from a third party and falsification by the third party can be prevented.

In the present invention, the image processing control data includes:
Various contents can be included. As an example, when the image data is defined in the YCbCr color space, it is desirable that the image processing control data include at least information on the color conversion from the YCbCr color space to the RGB color space. Depending on the color space conversion method, YCb
This is because the color defined in the Cr color space may not be completely reproduced in the RGB space. By including the information on the color conversion, it is possible to faithfully reproduce the colors of the original image even after the conversion. The information on the color conversion may include a name that can specify the color space after the conversion, or may include a conversion matrix used for the color conversion.

Information on color conversion is particularly useful when the RGB color space is a color space defined to have a wider color reproduction range than the sRGB color space. This is because sRGB is generally used in image processing, and when a color reproduction range wider than sRGB is required, it is necessary to specify a color conversion method and the like.

The digital watermarking technique may employ a method of embedding data in any one of bit planes of original image data, such as a pixel replacement type. When the original image data is converted to the frequency space and compressed at the time of generating the image data, the image processing control data may be embedded in the frequency space. In this case, the image processing control data is embedded avoiding the frequency deleted by the compression. As a method of converting to a frequency space and compressing, for example, JPEG using discrete cosine transform
The format is known, and in such a case, the image processing control data can be embedded in the high frequency region.
As another method, a compression method using a wavelet transform is also known. In such a case, image processing control data can be embedded in a low frequency region.

In the above description, the case where the image processing control data is embedded in the original image data has been described. The present invention
Alternatively, an image file in which original image data and image processing control data are stored in association with each other may be input, and the image processing control data may be digitally watermarked and re-embedded in the original image data.

Further, the present invention can be configured as an image processing apparatus for performing image processing based on image data in which image processing control data is digitally watermarked and embedded. Such an image processing device extracts image processing control data from image data and executes image processing based on the extracted data. If the digital watermarking method used when generating the image data is known, the image processing control data can be extracted relatively easily, and the image processing can be performed. The target of the image processing may be image data in a state where the image processing control data is included, or may be original image data after the image processing control data is separated.

The present invention can be configured in various aspects other than the aspects as the image data generating apparatus and the image processing apparatus described above. For example, it may be configured as an image data generation method or an image processing method. Also, an image data generation device,
It may be configured as a computer program for realizing the function as an image processing apparatus using a computer, and a storage medium storing such a program. Examples of the storage medium include a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punched card, a printed matter on which a code such as a barcode is printed, an internal storage device of a computer (a memory such as a RAM or a ROM), and the like. Various computer-readable media such as an external storage device can be used.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image file generating apparatus, an output apparatus, and an image processing system according to the present invention will be described based on some embodiments with reference to the drawings in the following order. A. B. Basic configuration of image processing system Image file generation device C. Output device D. Structure of image file F. Image processing in image file generation device Image processing in output device

A. Basic Configuration of Image Processing System: A basic configuration of an image processing system that can be commonly used in each embodiment will be described with reference to FIG. FIG. 1 is an explanatory diagram illustrating an example of a basic configuration of an image processing system.

The image processing system executes an image processing based on an input device for generating an image file, a digital still camera 12 as an image file generating device, and an image file generated by the digital still camera 12.
A color printer 20 is provided as an output device for outputting an image. If the color printer 20 is a general printer without an image processing function, it receives an image file from the digital still camera 12 and performs necessary image processing, and then prints the print data to the color printer 2.
0 is included in the image processing system.

Further, it is connected to a personal computer PC, a color printer 20, and a digital still camera 12 via a network, stores image data GD, executes image processing on an image file, and sends it back to a personal computer PC or the like. A server SV having a function may be included in the image processing system. With reference to FIG. 2, an exemplary configuration when image processing is performed via a network will be described. FIG. 2 is an explanatory diagram illustrating an exemplary image processing system including an input device that generates an image file, an output device that outputs an image file, and a server that performs image processing on the image file.

Digital still camera 12, scanner SC, digital video camera DVC as input device
Transmits an image file to be subjected to image processing to the server SV via the personal computer PC and the network. The digital still camera 12 or the like transmits the image file to the personal computer PC by wired communication using the cable CV. Alternatively, when the digital still camera 12, the scanner SC, and the digital video camera DVC have a wireless communication function, the digital still camera 12, the scanner SC, and the digital video camera DVC transmit the image file to the server SV through the wireless communication WL. Sent directly or over the network. The mobile terminal MB with an image generation function as an input device mainly uses the server SV via the wireless communication WL.
Send the image file to.

The image file that has been subjected to the image processing in the server SV is output to the printer 20 and the CR as output devices.
It is transmitted to a monitor (display device) 14 such as a T display or an LCD display, a projector, or the like. Printer 2
0, the monitor 14 is supplied with image data to be output via a network and a personal computer PC. The printer 20, the monitor 14, and the personal computer PC are connected by wire via a cable CV. Alternatively, when the printer 20 and the monitor 14 have a wireless communication function, the image file transmitted from the server SV is transmitted to the printer 20 and the monitor 14 by wireless communication WL directly or via a network. When an image file is transmitted from the server SV to the printer 20, image data in CMYK raster data format is transmitted. When an image file is transmitted from the server SV to the monitor 14, R
Preferably, image data in GB format is transmitted.

B. Image File Generating Apparatus With reference to FIG. 3, a basic configuration of the digital still camera 12 as an image file generating apparatus included in the image processing system will be described. FIG. 3 is a block diagram showing a schematic configuration of the digital still camera. The digital still camera 12 is a camera that obtains an image by forming light information on a digital device (CCD or photomultiplier tube), and includes a CCD or the like for collecting light information as shown in FIG. An optical circuit 121; an image acquisition circuit 122 for controlling the optical circuit 121 to acquire an image; an image processing circuit 123 for processing the acquired digital image; and a control circuit 124 including a memory and controlling each circuit. Have. The digital still camera 12 stores the obtained image as digital data in a memory card MC as a storage device. As a storage format of image data in the digital still camera 12, a JPEG format is generally used.
A storage format such as an IFF format, a GIF format, or a BMP format may be used.

In the present embodiment, the image data obtained here is image data defined in the YCbCr color space. Such a color space is used because it is a color space suitable for image compression in the JPEG format. However, processing from obtaining a voltage signal of the CCD to obtaining image data in the YCbCr space differs depending on the model of the digital still camera 12.

In the digital still camera 12, usually,
Image data defined in the RGB color space is once obtained from the CCD voltage signal. As the color space, a color space called sRGB or NTSC is properly used depending on the type of camera. Both spaces have a common point in that colors are defined in the RGB coordinate system, but NTSC uses sRGB.
This is a coordinate system with a wider color reproduction range than that of the coordinate system. The sRGB color space is usually defined in the range of 8 bits (0 to 255), but this range is extended to a negative value or a value of 256 or more (herein referred to as “extended sRGB space”). Is sometimes used. The information on the color space used at the time of shooting is included in color space parameters to be described later and attached to image data as information representing the color reproduction characteristics of the digital still camera 12. However, in this embodiment, since the extended sRGB space and the sRGB space have the same coordinate system, they are represented by the same parameters. The two may be distinguished from each other.

The image thus obtained in the RGB color space is
By performing a × 3 matrix operation, it is possible to convert to a YCbCr color space. This matrix is R
This converts the GB coordinate system to the YCbCr coordinate system, and a common matrix can be used regardless of whether the color space at the time of shooting is sRGB or NTSC.

The digital still camera 12 also stores individual image processing information (image processing parameters) such as brightness, contrast, exposure correction amount (exposure correction value), white balance, etc., and a plurality of image processing parameters in advance according to shooting conditions. A shooting mode in which values are set, a layout (arrangement) of image data GD, a selection / decision button 126 for setting the type of output device, a preview of a shot image,
A liquid crystal display 127 for setting a shooting mode and the like using the selection / decision button 126 is provided. Choice·
Procedures for setting the shooting mode, image processing parameters, layout, and the like using the determination button 126 and the liquid crystal display 127 will be described later in the corresponding embodiments.

The digital still camera 12 used in this image processing system uses image processing information GC of image data set by using the select / decide button 126 in addition to the image data GD as an image file as a memory card MC.
To be stored. That is, image processing information GC such as image processing parameters, layout, and shooting mode is automatically stored in the memory card MC as an image file together with the image data GD at the time of shooting. The image processing parameters include, in addition to the parameters and information set by the user, shooting conditions such as an exposure time, a white balance, an aperture, a shutter speed, and a lens focal length that are automatically set at the time of shooting. May be included. Parameters applied to each shooting mode, parameter values, layout information, output device information, and the like are stored in a memory in the control circuit 124 of the digital still camera 12.

The image file generated by the digital still camera 12 is sent to the color printer 20 via, for example, a cable CV, a computer PC, or a cable CV. Alternatively, the memory card MC storing the image file in the digital still camera 12 is connected to a computer PC mounted in the memory card slot or via the memory card M.
The image file is sent to the color printer 20 by connecting C directly to the printer 20. The image file is sent from the personal computer PC that has received the image file to the server SV via the network line, and after the image processing is executed, sent from the server SV to the personal computer PC or the color printer 20. In the following description of the output device, description will be made based on the case where the memory card MC is directly connected to the color printer 20.

C. Output device An output device constituting an image processing system with reference to FIG.
That is, a schematic configuration of the color printer 20 will be described. FIG. 4 is a block diagram showing a schematic configuration of the color printer 20.

The color printer 20 is a printer capable of outputting a color image. For example, four color inks of cyan (C), magenta (M), yellow (Y), and black (K) are printed on a printing medium. This is an inkjet printer that forms an image by ejecting ink to form a dot pattern. Alternatively, it is an electrophotographic printer that forms an image by transferring and fixing a color toner on a print medium. As the color ink, in addition to the above four colors, light cyan (light cyan, LC), light magenta (light magenta, LM), and dark yellow (dark yellow, DY) may be used.

As shown in the figure, the color printer 20
A mechanism for driving the print head 211 mounted on the carriage 21 to eject ink and form dots, a mechanism for reciprocating the carriage 21 in the axial direction of the platen 23 by the carriage motor 22, and a paper feed motor 24
And a control circuit 30 for transporting the printing paper P. The mechanism for reciprocating the carriage 21 in the axial direction of the platen 23 includes an endless drive between a carriage shaft 22 and a slide shaft 25 slidably holding the carriage 21 erected in parallel with the shaft of the platen 23. It is composed of a pulley 27 on which a belt 26 is stretched, a position detection sensor 28 for detecting the origin position of the carriage 21, and the like. The mechanism for transporting the printing paper P includes a platen 23,
It comprises a paper feed motor 24 for rotating the platen 23, a paper feed auxiliary roller (not shown), and a gear train (not shown) for transmitting the rotation of the paper feed motor 24 to the platen 23 and the paper feed auxiliary roller.

The control circuit 30 controls the operation panel 2 of the printer.
9 while appropriately controlling the movements of the paper feed motor 24, the carriage motor 22, and the print head 211. The printing paper P supplied to the color printer 20
Is set so as to be sandwiched between the platen 23 and the paper feed auxiliary roller, and is fed by a predetermined amount according to the rotation angle of the platen 23.

The carriage 21 has an ink cartridge 2
12 and the ink cartridge 213 are mounted. The ink cartridge 212 contains black (K) ink,
The ink cartridge 213 has another ink, that is,
In addition to three color inks of cyan (C), magenta (M) and yellow (Y), inks of a total of six colors of light cyan (LC), light magenta (LM) and dark yellow (DY) are stored.

Next, the internal configuration of the control circuit 30 of the color printer 20 will be described with reference to FIG. FIG. 5 is an explanatory diagram showing the internal configuration of the control circuit 30 of the color printer 20. As shown in FIG.
CPU 31, PROM 32, RAM 33, PCMCIA slot 34 for acquiring data from memory card MC,
A peripheral device input / output unit (PIO) 35 for exchanging data with the paper feed motor 24, the carriage motor 22, and the like, a timer 36, a drive buffer 37, and the like are provided. The drive buffer 37 includes ink ejection heads 214 to 220
Is used as a buffer for supplying a dot on / off signal to the. These are connected to each other by a bus 38 so that data can be exchanged with each other. The control circuit 30 includes an oscillator 3 that outputs a drive waveform at a predetermined frequency.
9 and a distribution output device 40 for distributing the output from the oscillator 39 to the ink ejection heads 214 to 220 at a predetermined timing.

The control circuit 30 reads the image file 100 from the memory card MC, analyzes the attached information AI,
Image processing is performed based on the analyzed control information AI.
The control circuit 30 outputs dot data to the drive buffer 37 at a predetermined timing while synchronizing with the movements of the paper feed motor 24 and the carriage motor 22.

D. Structure of Image File The contents of the image file GF that can be used in the image processing system will be described with reference to FIG. FIG. 6 is an explanatory diagram conceptually showing an example of the content of the image file GF. The image file GF includes an image data storage area 101 for storing the image data GD, and image processing information GC, layout information, and image data which are referred to and applied at the time of image processing of the image data GD in the color printer 20, the personal computer PC, and the server SV. An image processing information storage area 102 for storing data reference destination information is provided. Image data GD
Is stored in, for example, the JPEG format. Note that terms such as file structure, data structure, and storage area in this embodiment mean an image of a file or data in a state where the file or data is stored in the storage device.

In this embodiment, the image processing information GC is digitally watermarked and embedded in the image data GD as described later. In the drawing, the image processing information storage area 102 and the image data storage area 101 are shown separately for convenience of explanation, but in the actual file format, the former is scattered in the latter area.

The image processing information GC is information relating to the image quality when image data is generated (when photographed) by an image data generating device such as the digital still camera 12, such as exposure time, ISO sensitivity, aperture, and so on. Parameters related to shutter speed and focal length, and image processing parameters such as exposure correction amount, white balance, shooting mode, target color space, etc. arbitrarily set by the user, shooting mode, and individual image processing parameters according to the output characteristics of the output device including.

The image file GF according to this embodiment is
In addition to the digital still camera 12, an input device (image file generating device) such as a digital video camera and a scanner
Can also be generated by

In the figure, image data and image processing information GC
Although only the case where the image processing information includes only the image processing information such as the exposure time, the ISO sensitivity, the aperture, the shutter speed, and the focal length is described as being separately recorded in the header part of the image data or the like. Good. As a configuration of such an image file, for example, an image file format standard (Exif) for a digital still camera is used.

The control data is data for controlling the content of image processing to be performed on the image data when outputting the image. In the present embodiment, the control data is broadly classified and includes two types of data: a color space parameter and a color correction parameter.

The target color space is specified by a color space parameter. Here, the color space parameter is data for transmitting the color reproduction characteristics of the image file generation device to the output device side and realizing faithful color reproduction of the subject. These parameters include a gamma correction value according to the characteristics of the image file generation device and a parameter for specifying a color space conversion method. The designated parameter of the color space conversion method is a parameter that specifies a color conversion method used at the time of image processing according to the width of the color reproduction range by the image file generation device. In this embodiment, as described above,
The color space of sRGB and NTSC is used. Since the two have different color reproduction ranges, if the same conversion method is applied during image processing, the color reproduction range may be unnecessarily reduced. Therefore, by specifying the color conversion method by using the designated parameters, an attempt has been made to execute image processing that does not impair the color reproduction range at the time of shooting. The designated parameter can be set in various formats. In the present embodiment, the designated parameter is a parameter that designates whether the color space used at the time of shooting is sRGB or NTSC. The conversion matrix itself used for color space conversion may be used as the designated parameter.

E. Image Processing in Image File Generating Apparatus: FIG. 7 is a flowchart of image data generating processing in the embodiment. The processing contents in the digital still camera 12 are shown.

Control circuit 1 of digital still camera 12
In step S300, it is determined whether the user has set a shooting mode or image processing information GC (image processing parameters) such as a white balance and an exposure correction amount prior to shooting (step S300). These image processing information G
The setting of C is performed by operating the select / set button 126 and selecting the user from among the predetermined shooting modes displayed on the liquid crystal display 127 or by setting the desired brightness on the liquid crystal display 127. This is executed by the user setting image processing parameter values such as contrast, contrast and the like.

If the control circuit 124 determines that the optional image processing information GC has been set (step S300: Yes), the control circuit 124 sets the set image processing information in response to a photographing request, for example, pressing down a shutter button. Processing information GC
And the thumbnail data GDS of the image data GD are generated using the parameter values defined by the image processing information GC and the parameter values specified by the image processing information GC automatically set from the photographing conditions (step). S310). In contrast, the control circuit 12
When it is determined that the optional image processing information GC has not been set (step S300: No), the image processing information 4 is defined by the image processing information GC automatically set from the shooting conditions in response to the shooting request. The image data GD is generated using the parameter values, and the thumbnail data GDS of the image data GD is generated (step S320).

The control circuit 124 generates image processing information (step S340), converts the generated image processing information GC into a digital watermark, and embeds it in the image data GC (step S340).
360). The control circuit 124 transfers the image file GF including the digitally watermarked image data GD to the memory card M
Then, the processing routine is terminated.

FIG. 8 is an explanatory diagram showing an example of digital watermarking. In this method, the image processing information GC is embedded at the time of conversion to the JPEG format. The image data before processing is data having a gradation value for each pixel (hereinafter, referred to as gradation data) as shown on the left side of the drawing. The control circuit 124 performs a discrete cosine transform (DCT transform) on the gradation data. The DCT transform is performed on a block unit including some pixels in the grayscale data. In the figure, squares separated by broken lines indicate pixels, and portions separated by thick lines indicate blocks BL.
In this example, for convenience of illustration, a case where nine pixels form one block is illustrated, but a block often includes 8 × 8 pixels.

The gradation data is converted into a frequency space by DCT as shown in the center of the figure. The frequency space is a space in which a low-frequency component is allocated to each block BL in an upper left direction and a high-frequency component is allocated in a lower right direction.

Next, quantization is performed by dividing each component in the frequency space by a preset quantization table. This is a procedure of compression, and the quantization table is set so that a higher frequency component is quantized by a larger number.

In this embodiment, the image processing control information GC is embedded in the quantized data. The figure shows a bit string image of the image processing control information GC. Generally, high frequency component data is known as data having a small effect on an image. In this embodiment, by utilizing this characteristic, the bit string of the image processing control information GC is embedded in the component having the highest frequency. Regardless of the component value obtained by the quantized data, the data can be embedded by replacing the bit corresponding to the component with the highest frequency with the bit of the image processing control information GC.

At this time, in the quantized data, since the component having the highest frequency in one block is almost 0 due to the setting of the quantization table, only about 1 bit is embedded in one block. Can not do. Therefore, in this embodiment, as shown, the image processing information GC is scattered and embedded in a plurality of blocks. According to the general image data and the block size, it is possible to embed the image processing information GC using only the component having the highest frequency. However, when the number of blocks is insufficient, a plurality of components on the higher frequency side are used. It may be embedded by using.

After this processing, the compression processing called run-length compression and Huffman coding is performed, whereby the embedding of the image processing information GC using the digital watermark is completed.

F. Image Processing in Color Printer 20: FIG. 9 is a flowchart of image processing in the color printer 20. Control circuit 30 of color printer 20
When the memory card MC is inserted into the slot 34, the (CPU 31) reads the image file 1 from the memory card MC.
00 and read the read image file 100 into RA
It is temporarily stored in M33 (step S500). CP
U31 searches the read image file 100 for image processing information GC (step S510).

The image processing information GC is embedded in the image data GD after being converted into a digital watermark.
Extracts digitally watermarked image processing information GC. For the color printer 20 corresponding to the image file of the present embodiment, since the method of extracting the digitally watermarked information is known, the extraction can be performed relatively easily.

FIG. 10 is an explanatory diagram showing a method of extracting the image processing information GC. The image data GD can be restored to the quantized data shown on the left side of the figure by inverse processing of run-length compression and Huffman coding. The CPU 31 generates data in the frequency space by multiplying the quantization data by a quantization table. The quantization table used here is the same as the quantization table used when generating image data (see FIG. 8). By using this quantization table, data including image processing information GC can be obtained as shown in the upper part of the figure. In this embodiment, since the image processing information GC is embedded using the highest frequency component, the image processing information GC can be extracted by collecting a bit sequence corresponding to this component from each block. The image processing information GC
After the image processing information GC is extracted, the highest frequency component is replaced with 0 in order to avoid the effect of the bit corresponding to on the image itself. The highest frequency component is
Since the influence on the image is relatively small, the image processing information G
You can leave C embedded. By performing inverse DCT transform on the data in the frequency space obtained in this way, gradation data can be obtained.

The above-described processing may be performed for all the quantized data. However, in this embodiment, the quantization table is switched depending on whether or not the image processing information GC is embedded. That is, as shown in the lower part of FIG. 10, for the quantized data in which the image processing information GC is not embedded, a quantization table in which the highest frequency component becomes 0 is used. This table is the same as the table used at the time of compression. By using such a quantization table, the compression ratio of image data can be improved.

As a result of such extraction processing, the image processing information G
When C is searched and found (step S520: Y
es), the CPU 31 analyzes the contents (step S530). The CPU 31 analyzes the analyzed image processing information GC
Is performed based on the image data (step S540), the processed image data is subjected to halftone processing, and printed out (step S550).

When the image processing information cannot be searched and found (step S520: No), the CPU 31 cannot reflect the image processing information at the time of generating the image data. The stored image processing information, that is, various parameter values are acquired from the ROM 32, and normal image processing is executed (step S560). The CPU 31 prints out the processed image data (step S55).
0), end this processing routine.

FIG. 11 is a flowchart of the image processing based on the image processing information GC. This is a detailed description of the process of step S530 in FIG.

First, the CPU 31 converts the color space of the image data from the YCbCr color space to the RGB color space at the time of photographing (step S14). This conversion is performed using the inverse matrix of the matrix used in the conversion from the RGB space to the YCbCr space by the digital still camera 12. By this conversion, the image data is converted into a color space at the time of shooting, that is, one of NTSC, sRGB, and extended sRGB. When converted into the extended sRGB color space, at this point, a negative value and a value of 256 or more are included.

Next, the CPU 31 performs gamma correction on the image data (step S16). The gamma value used for the gamma correction is included in the image processing information GC as information indicating the characteristics of the digital still camera 12.

When the gamma correction is completed, a process of converting the color space of the image data into a wRGB color space defined by a color reproduction range wider than sRGB is performed. This is because if image data captured in the NTSC color space or the extended sRGB color space is processed in the sRGB color space having a narrow color reproduction range, the color of the subject may not be faithfully reproduced. From this viewpoint, the processing described below may be skipped for image data captured in the sRGB space. In this embodiment, since the color space information included in the image processing information GC does not distinguish between the sRGB space and the extended sRGB space, the image data photographed in the sRGB space is also converted to the wRGB space. And Even in such a case, in the extended sRGB space, since the image data includes a negative value or a value of 256 or more, the extended sRGB space and the sRGB space depend on the presence or absence of these gradation values.
It is possible to distinguish it from space.

The conversion process of the color space to wRGB is performed by a matrix operation. As explained earlier, CP
U31 handles image data defined in the sRGB color space or the extended sRGB color space, and image data defined in the NTSC color space. Although it is possible to define a matrix for directly converting from each color space to the wRGB color space, in the present embodiment, conversion is performed via a standard XYZ color space.

That is, the CPU 31 first performs conversion from the RGB color space to the XYZ color space (step S18).
This conversion process differs depending on the color space that defines the image data. That is, the sRGB color space or the extended sRGB
A conversion matrix TM1 for the color space and a conversion matrix TM2 for the NTSC color space are prepared in advance, and a conversion process corresponding to the color space at the time of shooting is realized by selectively using these two types. By this conversion, the image data shot in the individual color spaces is unified into the standard XYZ color space.

Next, the CPU 31 calculates w from the XYZ color space.
A conversion process to the RGB color space is performed (step S20).
This processing is also a matrix operation. Here, regardless of the color space at the time of shooting, conversion can be performed using a single matrix. The matrix used for the operation is w
It can be set arbitrarily according to the definition of the RGB color space.

As described above, since it is not necessary to convert image data photographed in the sRGB color space into a wider color space, steps S18 and S20 may be skipped. When the NTSC color space is used as a color space wider than the sRGB color space, for example, the processing of steps S18 and S20 may be skipped for image data captured in the NTSC color space. As described above, the processing in steps S18 and S20 can be appropriately omitted depending on the relative relationship between the color space used at the time of shooting and the color space finally used.

When the color space conversion process is completed, the CPU 3
1 performs inverse gamma correction (step S22). The gamma value used here is a value set based on the color reproduction characteristics of the output device. In this embodiment, since the model of the output device is known at the time of shooting, it is included in the image processing information GC attached to the image data in advance.

The CPU 31 further executes an image quality automatic adjustment process to reflect the intention at the time of photographing (step S24). In this embodiment, the image processing information GC includes adjustment parameters such as contrast as color correction parameters. The CPU 31 automatically adjusts the image quality based on the parameters. Since the image quality adjustment method based on each parameter is well known, detailed description will be omitted.

With the above processing, the correction processing of the image data reflecting the color reproduction characteristics of the digital still camera 12 and the intention at the time of photographing is completed. The CPU 31 performs a color conversion process on the RGB image data (step S2).
6). CMYK used in printer for RGB color system
This is a process of converting into the color system. This conversion is performed by referring to a conversion lookup table (LUT) that associates the two colors. In the case of the present embodiment, a table LUTw for conversion from the wRGB color space to CMYK is normally used. However, in order to be able to handle image data defined in the sRGB space, the image processing system also includes a conversion table LUTs for the sRGB color space, and these tables are converted according to the color space in which the image data is defined. I decided to use them properly. For example, when the color space conversion processing in steps S18 and S20 is skipped for image data captured in the sRGB space, the LUTs are output without performing any processing for adjusting image quality on the received image file. And so on.

The image data thus converted into the CMYK gradation values is subjected to halftone processing and printed by the processing in step S550 described above.

According to the system of the present embodiment described above, the image processing to be performed on the image data can be specified by the image processing information, and the image processing is performed without impairing the characteristics and intention at the time of generating the image data. be able to. Further, in the present embodiment, since the image processing information is embedded in the form of a digital watermark, the content can be kept secret from a third party and falsification by the third party can be prevented.

Further, by appropriately embedding the digital watermark information in the image data GD, even if the image data GD is clipped by specifying an arbitrary area, the image processing information can be added to the clipped image data. GC can be attached. Therefore, appropriate image processing can be performed on the clipped image data. Such embedding methods include:
For example, there is a method of embedding the image processing information GC in the image data with redundancy. That is, a method of embedding the same image processing information GC so that a plurality of sets can be obtained for the entire image data.

The digital watermarking technique is not limited to the method exemplified in the embodiment. For example, a method of embedding data in any bit plane of the original image data, such as a pixel replacement type, may be adopted. Further, a method of compressing image data using a wavelet transform may be used. In such a case, the image processing control data can be embedded in the low frequency region side.

The embodiment has exemplified the case where the image processing information is embedded in the image data photographed by the digital still camera. The generation of the image data may be performed by a computer or the like. For example, the image data may be embedded in image data input from the outside. Alternatively, an image file containing image processing information and image data that has not been digitally watermarked may be input, and the image processing information may be digitally watermarked and embedded.

In the embodiment, an example of application to a still image has been described, but the present invention is also applicable to moving image data such as MPEG. For example, image processing control data or other output control data may be added to a moving image file to perform output control on all or some frames of the moving image.

Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that various configurations can be adopted without departing from the spirit of the present invention. For example, the above-described control processing may be realized by software or hardware.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of a basic configuration of an image processing system.

FIG. 2 is an explanatory diagram illustrating an exemplary image processing system including an input device that generates an image file, an output device that outputs an image file, and a server that performs image processing of the image file.

FIG. 3 is a block diagram illustrating a schematic configuration of a digital still camera.

FIG. 4 is a block diagram showing a schematic configuration of the color printer 20.

FIG. 5 is an explanatory diagram showing an internal configuration of a control circuit 30 of the color printer 20.

FIG. 6 is an explanatory diagram conceptually showing an example of the contents of an image file GF.

FIG. 7 is a flowchart of a process of generating image data in the embodiment.

FIG. 8 is an explanatory diagram showing an example of digital watermarking.

FIG. 9 is a flowchart of image processing in the color printer 20.

FIG. 10 is an explanatory diagram showing a method of extracting image processing information GC.

FIG. 11 is a flowchart of image processing based on image processing information GC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 ... Digital still camera 14 ... Monitor (display device) 20 ... Color printer 21 ... Carriage 22 ... Carriage motor 23 ... Platen 24 ... Motor 25 ... Sliding shaft 26 ... Drive belt 27 ... Pulley 28 ... Position detection sensor 29 ... Operation panel DESCRIPTION OF SYMBOLS 30 ... Control circuit 34 ... Slot 37 ... Drive buffer 38 ... Bus 39 ... Oscillator 40 ... Distribution output device 100 ... Image file 101 ... Image data storage area 102 ... Image processing information storage area 121 ... Optical circuit 122 ... Image acquisition circuit 123 ... Image processing circuit 124 Control circuit 126 Selection / setting button 126 Selection / decision button 127 Liquid crystal display 211 Printhead 212 Ink cartridge 213 Ink cartridge 214 Ink ejection head

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/60 B41J 29/00 Z F-term (Reference) 2C061 AP01 AP06 CL10 5B057 BA02 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC01 CE08 CE17 CE18 CH08 5C076 AA14 AA26 BA06 5C077 LL14 LL19 MP08 PP23 PP32 PP34 PP37 PP49 PQ12 SS06 TT02 TT09 5C079 HB01 HB04 HB05 HB11 LA40 LB02 MA11 MA17 NA03 NA19 PA03 PA05

Claims (6)

[Claims] 1. An image data generating apparatus, comprising: an original image data input unit for inputting original image data; and an image for setting image processing control data for specifying contents of image processing to be performed on the original image data. An image data generating apparatus comprising: processing control data setting means; and image data generating means for generating image data in which the image processing control data is digitally watermarked and embedded in the original image data. 2. The image data generation device according to claim 1, wherein the image data is defined in a YCbCr color space, and the image processing control data includes at least a value from a YCbCr color space to an RGB color space. An image data generating device including information on color conversion. 3. The image data generating apparatus according to claim 2, wherein said RGB color space is a color space defined such that a color reproduction range is wider than an sRGB color space. 4. The image data generating device according to claim 1, wherein said image data generating means includes:
The image processing control data includes a compression unit that converts the original image data into a frequency space and compresses the converted data.
An image data generating device embedded so as to avoid a frequency deleted by the compression. 5. An image data generating apparatus, comprising: an image inputting an image file storing original image data and image processing control data for specifying contents of image processing to be performed on the original image data; An image data generating apparatus comprising: a file input unit; and an image data generating unit configured to generate image data in which the image processing control data is digitally watermarked and embedded in the original image data. 6. An image processing apparatus, comprising: image data input means for inputting image data in which image processing control data for specifying the content of image processing is digitally watermarked and embedded; An image processing apparatus comprising: an extraction unit that extracts processing control data; and an image processing unit that performs image processing based on the image processing control data.